One way of getting into a director's or artist's head is to look at patterns in their style. One pattern we see in a lot of Kubrick's work is musical irony. One example would be in Clockwork Orange, how Kubrick uses classical music in hyper violent, disturbing scenes. Another is in Dr. Strangelove, when he uses the upbeat toe-tapper "Vera Lynn" over scenes of atomic bomb mushroom clouds.

So if we've established that Kubrick likes to use musical irony, what does that say about 2001? In particular the epic theme Thus Spoke Zarathustra? The composition itself elicits ideas of majesty, triumph and ascension. The sort of stuff you feel when you win a marathon. But if Kubrick was using it ironically, then we can assume that it's not necessarily a feel-good moment.

That's sort of obvious when the ape is swinging his bone, killing other apes and slaughtering animals while the piece is playing. But how about the ending? The triumphant evolution of the next great species to supercede humans and its return to Earth in a glowing bubble. In light of Kubrick's use of the piece, maybe we should feel terrified?